PathScan® Phospho-Bad (Ser112) Sandwich ELISA Kit #7182

Figure 1. Treatment of OVCAR8 cells with TPA stimulates phosphorylation of Bad at Ser112, detected by PathScan® Phospho-Bad (Ser112) Sandwich ELISA Kit #7182, but does not affect the level of total Bad protein detected by PathScan® Total Bad Sandwich ELISA Kit #7162. Lambda phosphatase treatment of control cell lysates (4000 U/mL for 60 minutes at 37ºC) abolishes the basal phosphorylation of Bad as shown by both Sandwich ELISA and Western analysis. The absorbance readings at 450 nm are shown in the top figure, while the corresponding Western blots using Phospho-Bad (Ser112) Antibody #9296 (right panel) or Bad Antibody #9254 (left panel), are shown in the bottom figure.

Figure 2. The relationship between the protein concentration of lysates from untreated and TPA-treated OVCAR8 cells and the absorbance at 450 nm is shown. Cells were serum starved overnight and then treated with 200 nm TPA for 30 min. at 37ºC.

Gallery: PathScan® Phospho-Bad (Ser112) Sandwich ELISA Kit #7182

Figure 1. Treatment of OVCAR8 cells with TPA stimulates phosphorylation of Bad at Ser112, detected by PathScan® Phospho-Bad (Ser112) Sandwich ELISA Kit #7182, but does not affect the level of total Bad protein detected by PathScan® Total Bad Sandwich ELISA Kit #7162. Lambda phosphatase treatment of control cell lysates (4000 U/mL for 60 minutes at 37ºC) abolishes the basal phosphorylation of Bad as shown by both Sandwich ELISA and Western analysis. The absorbance readings at 450 nm are shown in the top figure, while the corresponding Western blots using Phospho-Bad (Ser112) Antibody #9296 (right panel) or Bad Antibody #9254 (left panel), are shown in the bottom figure.

Figure 2. The relationship between the protein concentration of lysates from untreated and TPA-treated OVCAR8 cells and the absorbance at 450 nm is shown. Cells were serum starved overnight and then treated with 200 nm TPA for 30 min. at 37ºC.

Protocol

ELISA Colorimetric (Lyophilized)

A. Solutions and Reagents

NOTE: Prepare solutions with purified water.

Microwell strips: Bring all to room temperature before use.

Detection Antibody: Supplied lyophilized as a green colored cake or powder. Add 1.0 ml of Detection Antibody Diluent (green solution) to yield a concentrated stock solution. Incubate at room temperature for 5 min with occasional gentle mixing to fully reconstitute. To make the final working solution, add the full 1.0 ml volume of reconstituted Detection Antibody to 10.0 ml of Detection Antibody Diluent in a clean tube and gently mix. Unused working solution may be stored for 4 weeks at 4°C.

HRP-Linked Antibody*: Supplied lyophilized as a red colored cake or powder. Add 1.0 ml of HRP Diluent (red solution) to yield a concentrated stock solution. Incubate at room temperature for 5 min with occasional gentle mixing to fully reconstitute. To make the final working solution, add the full 1.0 ml volume of reconstituted HRP-Linked Antibody to 10.0 ml of HRP Diluent in a clean tube and gently mix. Unused working solution may be stored for 4 weeks at 4°C.

Microcentrifuge for 10 min (x14,000 rpm) at 4°C and transfer the supernatant to a new tube. The supernatant is the cell lysate. Store at −80°C in single-use aliquots.

C. Test Procedure

After the microwell strips have reached room temperature, break off the required number of microwells. Place the microwells in the strip holder. Unused microwells must be resealed and stored at 4°C immediately.

Cell lysates can be undiluted or diluted with Sample Diluent (supplied in each PathScan® Sandwich ELISA Kit, blue color). Individual datasheets for each kit provide a sensitivity curve that serves as a reference for selection of an appropriate starting lysate concentration. The sensitivity curve shows typical kit assay results across a range of lysate concentration points.

Add 100 µl of each undiluted or diluted cell lysate to the appropriate well. Seal with tape and press firmly onto top of microwells. Incubate the plate for 2 hr at 37°C. Alternatively, the plate can be incubated overnight at 4°C.

Gently remove the tape and wash wells:

Discard plate contents into a receptacle.

Wash 4 times with 1X Wash Buffer, 200 µl each time for each well.

For each wash, strike plates on fresh towels hard enough to remove the residual solution in each well, but do not allow wells to completely dry at any time.

Clean the underside of all wells with a lint-free tissue.

Add 100 µl of reconstituted Detection Antibody (green color) to each well (refer to Section A, Step 2). Seal with tape and incubate the plate at 37°C for 1 hr.

Repeat wash procedure (Section C, Step 4).

Add 100 µl of reconstituted HRP-Linked secondary antibody (red color) to each well (refer to Section A, Step 3). Seal with tape and incubate the plate for 30 min at 37°C.

Repeat wash procedure (Section C, Step 4).

Add 100 µl of TMB Substrate to each well. Seal with tape and incubate the plate for 10 min at 37°C or 30 min at 25°C.

Add 100 µl of STOP Solution to each well. Shake gently for a few seconds.

NOTE: Initial color of positive reaction is blue, which changes to yellow upon addition of STOP Solution.

Product Description

CST's PathScan® Phospho-Bad (Ser112) Sandwich ELISA Kit is a solid phase sandwich enzyme-linked immunosorbent assay (ELISA) that detects endogenous levels of phospho-Bad (Ser112) protein. A Bad rabbit mAb has been coated onto the microwells. After incubation with cell lysates, Bad protein (phospho and nonphospho) is captured by the coated antibody. Following extensive washing, a phospho-Bad (Ser112) mouse mAb is added to detect the captured phospho-Bad protein. Anti-mouse IgG, HRP-linked Antibody is then used to recognize the bound detection antibody. HRP substrate, TMB, is added to develop color. The magnitude of absorbance for this developed color is proportional to the quantity of phospho-Bad (Ser112) protein.

Background

Bad is a proapoptotic member of the Bcl-2 family that promotes cell death by displacing Bax from binding to Bcl-2 and Bcl-xL (1,2). Survival factors, such as IL-3, inhibit the apoptotic activity of Bad by activating intracellular signaling pathways that result in the phosphorylation of Bad at Ser112 and Ser136 (2). Phosphorylation at these sites promotes binding of Bad to 14-3-3 proteins to prevent an association between Bad with Bcl-2 and Bcl-xL (2). Akt phosphorylates Bad at Ser136 to promote cell survival (3,4). Bad is phosphorylated at Ser112 both in vivo and in vitro by p90RSK (5,6) and mitochondria-anchored PKA (7). Phosphorylation at Ser155 in the BH3 domain by PKA plays a critical role in blocking the dimerization of Bad and Bcl-xL (8-10).